1. Field of the Invention
This invention relates generally to phonograph record players, and more particularly is directed to an improved phonograph record player control mechanism for effecting lead-in movement of a tone arm from an elevated rest position outside the perimeter of a turntable to a selected set-down position on a record supported by the turntable so as to commence a play operation, and for effecting a return movement of the tone arm to its rest position upon the termination of the play operation.
2. Description of the Prior Art
A so-called automatic phonograph record player is known in which the control mechanism thereof includes a drive gear rotatable with the turntable, a control gear having peripheral teeth engageable by the drive gear for turning the control gear to effect the lead-in and return movements of the tone arm by means of a lever assembly having a cam follower engaging a cam formed on the control gear, with the peripheral teeth of the control gear having two toothless gaps selectively facing the drive gear in stop and play positions, respectively, of the control gear, that is, when the tone arm is in its rest position and during a play operation, respectively. In order to avoid inadvertent turning of the control gear from its stop and play positions, the known control mechanism includes first and second recesses opening radially outward in a circumferential surface of the control gear and being located to receive first and second locking pins on respective spring biased levers when the control gear is in its stop position with one of its toothless gaps facing the drive gear, and when the control gear is in its play position with its other toothless gap facing the drive gear, respectively. The foregoing arrangement for holding the control gear against inadvertent turning from its stop and play positions is undesirable in that it is relatively complicated, and in that the two recesses for receiving the respective locking pins on the spring biased levers have to be exactly positioned in respect to the corresponding toothless gaps of the control gear and also in respect to the cam of the latter for effecting the lead-in and return movements of the tone arm. Thus, it is difficult with the described arrangement to accurately position the control gear for the rest position of the tone arm and for the play operation. Moreover, since the locking pins on the spring biased levers are continuously pressed against a circumferential surface of the control gear, the spring biased levers exert a braking effect on the control gear during the turning of the latter for effecting the lead-in and return movements.
In most of the existing fully automatic phonograph record players in which the lead-in and return movements of the tone arm are automatically effected, the tone arm is free to swing in the direction in which it is being propelled relative to the tone arm drive mechanism by which the swinging of the tone arm is effected during the lead-in and return operations. Therefore, by reason of the inertia of the tone arm, the latter is apt to move beyond the desired set-down position during the lead-in operation, and to rebound from the arm rest at the conclusion of the return operation. Although an existing phonograph record player applies a brake force directly to the tone arm before the latter reaches the arm rest during a return operation, such known record player does not apply a braking force to the tone arm during the lead-in operation as well as during the return operation, so that uncertainty or variations in the set-down position are still possible during the lead-in operation.